Older people who don't expect a satisfying future may be more likely to live longer, healthier lives than those who see brighter days ahead, according to a paper inPsychology and Aging.

Scholars examined data collected from 1993 to 2003 for the national German Socio-Economic Panel, an annual survey of private households consisting of approximately 40,000 people 18 to 96 years old. The researchers divided the data according to age groups: 18 to 39 years old, 40 to 64 years old and 65 years old and above.

Through mostly in-person interviews, respondents were asked to rate how satisfied they were with their lives and how satisfied they thought they would be in five years.

Five years after the first interview, 43 percent of the oldest group had underestimated their future life satisfaction, 25 percent had predicted accurately and 32 percent had overestimated, according to the study. Based on the average level of change in life satisfaction over time for this group, each increase in overestimating future life satisfaction was related to a 9.5 percent increase in reporting disabilities and a 10 percent increased risk of death, the analysis revealed.

"Our findings revealed that being overly optimistic in predicting a better future was associated with a greater risk of disability and death within the following decade," said lead author Frieder R. Lang, PhD, of the University of Erlangen-Nuremberg in Germany. "Pessimism about the future may encourage people to live more carefully, taking health and safety precautions."

Because a darker outlook on the future is often more realistic, older adults' predictions of their future satisfaction may be more accurate, according to the survey analysis. In contrast, the youngest group had the sunniest outlook while the middle-aged adults made the most accurate predictions, but became more pessimistic over time.

"Unexpectedly, we also found that stable and good health and income were associated with expecting a greater decline compared with those in poor health or with low incomes," Lang said. "Moreover, we found that higher income was related to a greater risk of disability."

The researchers measured the respondents' current and future life satisfaction on a scale of 0 to 10 and determined accuracy in predicting life satisfaction by measuring the difference between anticipated life satisfaction reported in 1993 and actual life satisfaction reported in 1998. They analyzed the data to determine age differences in estimated life satisfaction; accuracy in predicting life satisfaction; age, gender and income differences in the accuracy of predicting life satisfaction; and rates of disability and death reported between 1999 and 2010. Other factors, such as illness, medical treatment or personal losses, may have driven health outcomes, the study said.

The findings do not contradict theories that unrealistic optimism about the future can sometimes help people feel better when they are facing inevitable negative outcomes, such as terminal disease, according to the authors. "We argue, though, that the outcomes of optimistic, accurate or pessimistic forecasts may depend on age and available resources," Lang said. "These findings shed new light on how our perspectives can either help or hinder us in taking actions that can help improve our chances of a long healthy life."